It works
It works as advertised. Used it in 90heat last weekend and it speed up the cool down process on my bolt gun and my AR's. My bolt gun had no issues with getting the unit into the receiver and cooling down the barrel after a string of shots. The unit really isn't optimized for an AR15 pattern rifle, as it doesn't fit thru the ejection port to line up directly with the chamber and bore, but you can finesse the rubber sealing piece into the barrel extension and blow some air thru the bore to speed up the cooling process. The RifleKuhl is a must have if you're shooting a suppressed rifle. This particular one had a whine to it when running, so I wrapped a couple of rubber bands around the unit and the whine went away.
